Chapter 2 - A Crash Course into Python - Lists section errors.

A Crash Course into Python chapter - lists section

The slicing explanation contains mistakes:

crash_course_in_python.py Lines 149:156

first_three = x[:3]                 # [-1, 1, 2]
three_to_end = x[3:]                # [3, 4, ..., 9]
one_to_four = x[1:5]                # [1, 2, 3, 4]
last_three = x[-3:]                 # [7, 8, 9]
without_first_and_last = x[1:-1]    # [1, 2, ..., 8]
copy_of_x = x[:]                    # [-1, 1, 2, ..., 9]

every_third = x[::3]                 # [-1, 3, 6, 9]

instead of index -1 in the explanations/comments should be used 0. -1 refers to the last element of the list/slice.

See also slicings The lower and upper bound expressions, if present, must evaluate to plain integers; defaults are zero and the sys.maxint, respectively.